#!/bin/sh
#
# rc This file is responsible for starting/stopping
# services when the runlevel changes.
#
# Optimization feature:
# A startup script is _not_ run when the service was
# running in the previous runlevel and it wasn‘t stopped
# in the runlevel transition (most Debian services don‘t
# have K?? links in rc{1,2,3,4,5} )
#
# Author: Miquel van Smoorenburg <[email protected]>
# Bruce Perens <[email protected]>
#
# Version: @(#)rc 2.78 07-Nov-1999 [email protected]
#
# 一. 参考文档：
# 1. inittab脚本启动解析
# http://blog.chinaunix.net/uid-17188120-id-4073497.html
# 2. Customizing the SDK Splash Screen
# http://processors.wiki.ti.com/index.php/Customizing_the_SDK_Splash_Screen
# 3. psplash进度条旋转成功
# http://www.xuebuyuan.com/1511619.html
#
# 2016-1-9 深圳 南山平山村 曾剑锋
##
##
## /etc/default/rcS
##
## Default settings for the scripts in /etc/rcS.d/
##
## For information about these variables see the rcS(5) manual page.
##
## This file belongs to the "initscripts" package.
#
## delete files in /tmp during boot older than x days.
## ‘0‘ means always, -1 or ‘infinite‘ disables the feature
#TMPTIME=0
#
## spawn sulogin during boot, continue normal boot if not used in 30 seconds
#SULOGIN=no
#
## do not allow users to log in until the boot has completed
#DELAYLOGIN=no
#
## assume that the BIOS clock is set to UTC time (recommended)
#UTC=yes
#
## be more verbose during the boot process
#VERBOSE=no
#
## automatically repair filesystems with inconsistencies during boot
#FSCKFIX=no
. /etc/default/rcS
export VERBOSE
# 在rcS中设置的一些环境变量
# PATH=/sbin:/bin:/usr/sbin:/usr/bin
# runlevel=S
# prevlevel=N
# umask 022
# export PATH runlevel prevlevel
#
# exec /etc/init.d/rc S
# 这个函数名可以认为是重置进度条进度
startup_progress() {
# 当前进度大小=上一次的进度+上每次的进度的变化值
step=$(($step + $step_change))
if [ "$num_steps" != "0" ]; then
# 这里相当于重新计算当前step占进度条的百分比
progress=$((($step * $progress_size / $num_steps) + $first_step))
else
# 直接就是100%了
progress=$progress_size
fi
#echo "PROGRESS is $progress $runlevel $first_step + ($step of $num_steps) $step_change $progress_size"
#if type psplash-write >/dev/null 2>&1; then
# TMPDIR=/mnt/.psplash psplash-write "PROGRESS $progress" || true
#fi
# 将上面的progress的值写入fifo中去，echo的值是固定的。
if [ -e /mnt/.psplash/psplash_fifo ]; then
echo "PROGRESS $progress" > /mnt/.psplash/psplash_fifo
fi
}
#
# Start script or program.
#
# 启动脚本函数
startup() {
# Handle verbosity
# VERBOSE=no, 不显示这一部分内容
[ "$VERBOSE" = very ] && echo "INIT: Running [email protected]"
case "$1" in
*.sh)
# Source shell script for speed.
# 这里相当于直接执行脚本，丢弃了参数
(
trap - INT QUIT TSTP
scriptname=$1
shift
. $scriptname
)
;;
*)
# 执行参数里命令
"[email protected]"
;;
esac
startup_progress
}
# Ignore CTRL-C only in this shell, so we can interrupt subprocesses.
# 这里就是捕捉INT QUIT TSTP三个信号，执行“：”，实际就是忽略这三个信号，防止脚本执行时使用ctrl-C 就退出脚本
trap ":" INT QUIT TSTP
# Set onlcr to avoid staircase effect.
# 设置onlcr避免楼梯的效果。
stty onlcr 0>&1
# Now find out what the current and what the previous runlevel are.
runlevel=$RUNLEVEL
#echo "danny add"
echo $2
sleep 5
# Get first argument. Set new runlevel to this argument.
# 由于传进来的参数的$1=S，所以这里可以断定的是runlevel是S
[ "$1" != "" ] && runlevel=$1
if [ "$runlevel" = "" ]
then
echo "Usage: $0 <runlevel>" >&2
exit 1
fi
# 目前没有看到由有关PREVLEVEL相关的内容，这里previous是N
previous=$PREVLEVEL
[ "$previous" = "" ] && previous=N
export runlevel previous
# Is there an rc directory for this new runlevel?
if [ -d /etc/rc$runlevel.d ]
then
# Find out where in the progress bar the initramfs got to.
PROGRESS_STATE=0
#if [ -f /dev/.initramfs/progress_state ]; then
# . /dev/.initramfs/progress_state
#fi
# Split the remaining portion of the progress bar into thirds
# 感觉这里可以认为是：已经出了一部分的脚本了，这部分内容也应该算进去
# 所以给出一部分进度条的空间出来，这样，进度条就不像是从0开始，至少
# 当我们看到图像的时候，psplash这个进程已经跑起来了。
progress_size=$(((100 - $PROGRESS_STATE) / 3))
# 这里的runlevel是S
case "$runlevel" in
0|6)
# Count down from -100 to 0 and use the entire bar
first_step=-100
progress_size=100
step_change=1
;;
S)
# Begin where the initramfs left off and use 2/3
# of the remaining space
first_step=$PROGRESS_STATE
progress_size=$(($progress_size * 2)) # 剩下2/3
step_change=1
;;
*)
# Begin where rcS left off and use the final 1/3 of
# the space (by leaving progress_size unchanged)
first_step=$(($progress_size * 2 + $PROGRESS_STATE))
step_change=1
;;
esac
num_steps=0
for s in /etc/rc$runlevel.d/[SK]*; do
case "${s##/etc/rc$runlevel.d/S??}" in
gdm|xdm|kdm|reboot|halt)
break
;;
esac
num_steps=$(($num_steps + 1))
done
step=0
# First, run the KILL scripts.
# 先结束掉需要结束的进程
if [ $previous != N ]
then
for i in /etc/rc$runlevel.d/K[0-9][0-9]*
do
# Check if the script is there.
[ ! -f $i ] && continue
# Stop the service.
startup $i stop
done
fi
# Now run the START scripts for this runlevel.
for i in /etc/rc$runlevel.d/S*
do
[ ! -f $i ] && continue
# 这里的previous=N，可以不用关心
if [ $previous != N ] && [ $previous != S ]
then
#
# Find start script in previous runlevel and
# stop script in this runlevel.
#
suffix=${i#/etc/rc$runlevel.d/S[0-9][0-9]}
stop=/etc/rc$runlevel.d/K[0-9][0-9]$suffix
previous_start=/etc/rc$previous.d/S[0-9][0-9]$suffix
#
# If there is a start script in the previous level
# and _no_ stop script in this level, we don‘t
# have to re-start the service.
#
[ -f $previous_start ] && [ ! -f $stop ] && continue
fi
case "$runlevel" in
0|6)
startup $i stop
;;
*)
startup $i start
;;
esac
done
fi
#Uncomment to cause psplash to exit manually, otherwise it exits when it sees a VC switch
if [ "x$runlevel" != "xS" ] && [ ! -x /etc/init.d/xserver-nodm ]; then
. /etc/init.d/qt.sh
# if type psplash-write >/dev/null 2>&1; then
# TMPDIR=/mnt/.psplash psplash-write "QUIT" || true
# umount /mnt/.psplash
# fi
fi
时间： 2024-10-10 10:04:05